miR-124-1 is a tumour suppressor microRNA (miR). Epigenetic deregulation of miRs is implicated in carcinogenesis. Promoter DNA methylation and histone modification of miR-124-1 was studied in 5 normal marrow controls, 4 lymphoma, 8 multiple myeloma (MM) cell lines, 230 diagnostic primary samples of acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL), chronic myeloid leukaemia (CML), chronic lymphocytic leukaemia (CLL), MM, and non-Hodgkin's lymphoma (NHL), and 53 MM samples at stable disease or relapse. Promoter of miR-124-1 was unmethylated in normal controls but homozygously methylated in 4 of 4 lymphoma and 4 of 8 myeloma cell lines. Treatment of 5-Aza-2′-deoxycytidine led to miR-124-1 demethylation and re-expression of mature miR-124, which also associated with emergence of euchromatic trimethyl H3K4 and consequent downregulation of CDK6 in myeloma cells harboring homozygous miR-124-1 methylation. In primary samples at diagnosis, miR-124-1 methylation was absent in CML but detected in 2% each of MM at diagnosis and relapse/progression, 5% ALL, 15% AML, 14% CLL and 58.1% of NHL (p<0.001). Amongst lymphoid malignancies, miR-124-1 was preferentially methylated in NHL than MM, CLL or ALL. In primary lymphoma samples, miR-124-1 was preferentially hypermethylated in B- or NK/T-cell lymphomas and associated with reduced miR-124 expression. In conclusion, miR-124-1 was hypermethylated in a tumour-specific manner, with a heterochromatic histone configuration. Hypomethylation led to partial restoration of euchromatic histone code and miR re-expression. Infrequent miR-124-1 methylation detected in diagnostic and relapse MM samples showed an unimportant role in MM pathogenesis, despite frequent methylation found in cell lines. Amongst haematological cancers, miR-124-1 was more frequently hypermethylated in NHL, and hence warrants further study.

Background. To examine the results of treatment of Extramammary Paget's disease (EMPD) in ethnic Chinese. Method. Between 1990 and 2010, patients treated for EMPD were reviewed. Data were analyzed retrospectively. Results. Forty-eight patients were treated by surgical resection. Local recurrence rate was 14.6%. The postresection defects were repaired by primary closure (8.3%), partial thickness skin graft (72.9%), or local/regional flaps (18.8%). Dermal invasion was found in 9 patients (18.8%). Seven patients (14.6%) developed regional lymph node metastasis (concurrent with surgery, n = 1; subsequent to surgery, n = 6), and 3 patients (6.3%) had systemic metastasis after surgery. The presence of dermal invasion was associated with significantly higher incidence of regional lymph nodes and systemic metastasis. The incidence of associated internal malignancy was 8.3%. Conclusion. The mainstay of treatment for EMPD is surgery. Pathological dermal invasion increases the chance of regional lymph node as well as systemic metastasis. The association with internal malignancy warrants preoperative endoscopic examination in all patients.

No abstract